C++ Mathematical Expression Library (ExprTk)  https://www.partow.net/programming/exprtk/index.html

exprtk_simple_example_05.cpp

diff --git a/exprtk_simple_example_05.cpp b/exprtk_simple_example_05.cpp
index 1002300..939b765 100644
--- a/exprtk_simple_example_05.cpp
+++ b/exprtk_simple_example_05.cpp
@@ -28,7 +28,7 @@
 
    myfunc()
    : exprtk::ifunction<T>(2)
-   {}
+   { exprtk::disable_has_side_effects(*this); }
 
    inline T operator()(const T& v1, const T& v2)
    {

exprtk_simple_example_12.cpp

diff --git a/exprtk_simple_example_12.cpp b/exprtk_simple_example_12.cpp
index 1aed5af..61af16b 100644
--- a/exprtk_simple_example_12.cpp
+++ b/exprtk_simple_example_12.cpp
@@ -47,7 +47,7 @@
                   "   upper_bound -= 1;                               "
                   " until (not(swapped) or (upper_bound == 0));       ";
 
-   T v[] = { T(2.2), T(1.1), T(5.5), T(4.4), T(3.3) };
+   T v[] = { T(9.9), T(2.2), T(1.1), T(5.5), T(7.7), T(4.4), T(3.3) };
 
    symbol_table_t symbol_table;
    symbol_table.add_vector("v",v);

exprtk_simple_example_15.cpp

diff --git a/exprtk_simple_example_15.cpp b/exprtk_simple_example_15.cpp
index 4808d17..bae566b 100644
--- a/exprtk_simple_example_15.cpp
+++ b/exprtk_simple_example_15.cpp
@@ -61,7 +61,6 @@
    expression.register_symbol_table(symbol_table);
 
    parser_t parser;
-
    parser.compile(bsm_model_program,expression);
 
    {